This invention relates to semiconductor packages with multiple electrically conductive leads extended from a central body of the package, and more particularly to carriers for accurately mounting such packages for their protection and electrical testing.
Leaded semiconductor packages frequently are mounted in protective carriers. The carriers protect the semiconductor packages against mechanical damage during shipping and handling, and also properly align the semiconductor package, particularly its conductive leads, relative to electrical hardware used in testing the package.
One known technique for accurately aligning the leaded semiconductor package within the protective carrier is to form multiple parallel ribs or rises in the carrier, with each rib or rise disposed between a pair of adjacent parallel leads. With the leads so positioned, the package is accurately aligned with respect to the carrier. For a typical package including a rectangular package body and leads projected outwardly of the body's sides, the ribs secure the package against movement parallel to the major plane of the package, i.e. in mutually perpendicular X and Y directions. A spring loaded beak, latch, snap-on lid or other retainer is used to secure the package in a Z direction orthogonal to the major plane.
Due to the generally poor tolerances associated with the semiconductor package body itself, the semiconductor package body cannot be used to align the package in the X and Y directions. Rather, the ribs or rises of the carrier provide the mechanical means by which the package is aligned in the X and Y directions. A problem with this arrangement, however, is that only these ribs or rises which are in direct contact with the package leads directly prevent the entire semiconductor package from moving significantly in either the X or Y direction. If the carrier and package experience sudden impact during handling or shipping, the ribs or rises prevent the leads from significant movement where as the semiconductor package body, because of its typically poor dimensional tolerances, is not restricted from movement. Consequently this can result in damage or bending of the package leads which will adversely affect the lead true position and subsequent manufacturing operations.
Therefore, it is an object of the present invention to provide a means for aligning a semiconductor package and carrier without providing lead positioning ribs formed on the carrier.
Another object is to provide a means for mounting an integrated circuit package and carrier, in which forces due to any sudden impact are distributed substantially to non-critical locations or features which do not affect the package lead true position or result in damage to the package leads.
Another object is to provide a means for accurately aligning an integrated circuit package relative to a carrier, while electrically isolating the leads from one another to permit electrical testing of the package while mounted on the carrier.
Yet another object is to provide a process for forming a dielectric connection of the leads of an integrated circuit package initially having an electrically conductive lead interconnection, and for later removing the conductive interconnection to electrically isolate the leads.